1. Field of the Invention
The present invention relates to an airplane wing structure having first and second spars extending in the span direction; a plurality of stringers disposed between the first and second spars and extending in the span direction; a rib extending in the chord direction and providing a connection between the first and second spars; and a skin covering the first and second spars, the stringer, and an upper face and a lower face of the rib.
2. Description of the Related Art
An airplane wing structure is disclosed in Japanese Patent Application Laid-open No. 2002-302097 or Published Japanese Translation (PCT) No. 2000-506816.
In general, a rib for defining the airfoil of an airplane wing is formed by press forming a thin plate material in order to lighten the weight. In addition, a stringer through hole is formed in an upper edge and a lower edge of the rib with a stringer fixed to an inner face of a skin of the wing and positioned through the stringer through hole via a gap. The wing is formed as a box structure that is resistant to bending or twisting by joining a spar, the stringer, the rib, and the skin, but when lift or drag acts on the wing, there is a possibility that the rib, which is formed from a thin plate material, will buckle due to the shear load. In the arrangements disclosed in Japanese Patent Application Laid-open No. 2002-302097 and Published Japanese Translation (PCT) No. 2000-506816, when press forming the rib, a bead extending in the vertical direction (wing thickness direction) is formed integrally with the rib, thereby enhancing the buckling strength of the rib toward a shear load.